Theory crack deflection

Faber, K.T. and Evans, G.A. Crack deflection processes theory and experiment ,... 

Crack deflection theory suggests that, for a given volume fraction, rodshaped obstacles will increase toughness more than disc-shaped obstacles. True or False ... 

K. T. Faber, A. G. Evans, Crack deflection processes-1. Theory. Acta Metall. 31 (1983) 565-576. 

The energy balance theory of fracture also predicted that crack deflection should be somewhat easier in the centre of the sample than on the outer surface. 

Faber, K., Evans, A., 1983. Crack deflection processes-I. Theory. ActaMetaUurgica 31,565—576. 

Equation 20 can be derived from the simple beam theory for a cantilever and linear elastic-considerations. For a cantilever beam of thickness t and length a (i.e.. one of the two halves of the DCB specimen with a crack length a) under an end load of P. the beam-end deflection 5/2 (equivalent to one-half of the load point displacement of the DCB specimen) is given by the beam theory... 

This section considers plate and membrane behavior, as opposed to scenarios where the film is thick enough to be considered an elastic half-space (as in Figure 39.2a). Thus, the applications in Section 39.4.2 thus correspond directly to the theory described in Section 39.3.2. The analysis of two relatively thick films (compared to crack length) requires numerical solutions not discussed in Section 39.3.2 and hence is discussed in Section 39.4.3.1 in conjunction with pressure-deflection relationships. 

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